5.4.2 Power Management Unit (PMU)

The Power Management Unit interface provides monitoring and management of the robot’s power system, including battery status, voltage and current monitoring, and more.

Core Features

Battery Monitoring

• Battery Voltage: Real-time monitoring of battery voltage

• Battery Current: Monitors battery charging/discharging current

• Battery Health: Tracks overall battery health status

Power Management

• Multi-channel Power Rails: Monitors 48V, 12V, 5V and other power rails

• Current Monitoring: Tracks current consumption of each module

• Voltage Monitoring: Tracks voltage status of each module

System Monitoring

• Module Power Status: Power status of RK3588, ORIN, etc.

• Over-current Protection: Detects and protects against over-current conditions

Power Management Topic

Topic Name	Data Type	Description	QoS	Frequency
/aima/hal/pmu/state	PmuState	Power management data	BEST_EFFORT+TRANSIENT_LOCAL	1Hz

• PmuState ros2-msg @ hal/msg/PmuState.msg

  # PMU State
  string pmu_software_version     # PMU software version
  string pmu_hardware_version     # PMU hardware version
  string pmu_protocol_version     # PMU protocol version
  uint32 pmu_bool_status          # Boolean status bits
  
  # Current info (unit: A)
  float64 head_power_current      # Head module current
  float64 output_48v_current      # 48V output current
  float64 rk3588_current          # RK3588 current
  float64 output_12v_current      # 12V output current
  float64 bus_48v_current         # 48V bus current
  float64 orin_current            # ORIN current
  
  # Voltage info (unit: V)
  float64 bus_48v_pmos_voltage    # 48V PMOS voltage
  float64 battery_voltage         # Battery voltage
  float64 fan_voltage             # Fan voltage
  float64 output_12v_voltage      # 12V output voltage
  float64 output_48v_voltage      # 48V output voltage
  float64 bus_48v_voltage         # 48V bus voltage
  float64 head_power_voltage      # Head module voltage
  float64 orin_voltage            # ORIN voltage
  float64 rk3588_voltage          # RK3588 voltage
  
  # Misc info
  float64 fan_speed               # Fan speed (RPM)
  uint8 fan_pecentage             # Fan percentage (%)
  float64 pmu_temperature         # PMU temperature (°C)
  
  # BMS info
  string bms_manufacturer         # BMS manufacturer
  string bms_serial_number        # BMS serial number
  string bms_hardware_version     # Hardware version
  string bms_software_version     # Software version
  
  uint32 bms_status_bits                      # Status bits
  
  uint16 battery_balance_line_resistance      # Cell balancing line resistance (mΩ)
  float64 battery_pack_voltage                # Pack voltage (V)
  float64 battery_current                     # Pack current (A, +charge / –discharge)
  float64 battery_output_power                # Pack output power (W)
  float64 battery_temperature                 # Pack temperature (°C)
  uint32 battery_remaining_capacity           # Remaining capacity (mAh)
  uint8 battery_remaining_capacity_percentage # Remaining capacity (%)
  uint16 battery_cycle_count                  # Cycle count
  uint32 battery_cycle_total_capacity         # Accumulated capacity (Ah)
  

Note

BMS field staleness: BMS-related fields (battery_pack_voltage, battery_current, battery_temperature, etc.) are only updated when BMS communication is normal. When BMS communication is abnormal, these fields retain their last valid values and are not cleared. Refer to diagnostic codes to determine data freshness.

pmu_bool_status Boolean Bit Definitions:

Bit	Name	Description
0	rk3588PowerGood	RK3588 power good
1	rk3588Monitor1	RK3588 monitor status 1
2	rk3588Monitor2	RK3588 monitor status 2
3	orinPowerGood	ORIN power good
4	orinMonitor1	ORIN monitor status 1
5	orinMonitor2	ORIN monitor status 2
6	bus48vOverCurrent	48V bus over-current
7	bus48vOverTemperature	48V bus over-temperature
8	rk3588PlugDetect	RK3588 plug detect
9	orinNXPlugDetect	ORIN NX plug detect
10-31	reserved	reserved bits

bms_status_bits Bit Definitions:

Bit	Name	Description
0	chargeFlag	Charging flag
1	chargeOverCurrentFlag	Charge over-current flag
2	dischargeFlag	Discharging flag
3	dischargeOverCurrentFlag	Discharge over-current flag
4	shortCircuitFlag	Battery short-circuit flag
5	cellOverVoltageFlag	Cell over-voltage flag
6	cellUnderVoltageFlag	Cell under-voltage flag
7	batteryOverVoltageFlag	Pack over-voltage flag
8	batteryUnderVoltageFlag	Pack under-voltage flag
9	cellOpenCircuitFlag	Cell open-circuit detected
10	ntcOpenCircuitFlag	Temperature sensor open-circuit detected
11	cellDischargeOverTemperatureFlag	Cell temperature above discharge upper limit
12	cellChargeOverTemperatureFlag	Cell temperature above charge upper limit
13	cellDischargeUnderTemperatureFlag	Cell temperature below discharge lower limit
14	cellChargeUnderTemperatureFlag	Cell temperature below charge lower limit
15	reserved_1	reserved bits
16	cellMaxVoltageDiffOverHighFlag	Max cell voltage difference above limit
17	mosfetChargeDisableFlag	MOSFET charge disabled
18	mosfetDischargeDisableFlag	MOSFET discharge disabled
19	mosfetOverTemperatureFlag	MOSFET over-temperature flag
20	balanceLineResistanceOverHighFlag	Balancing line resistance over limit
21-31	reserved_11	reserved bits

For the LED strip state topic (/aima/hal/pmu/led_state), see LED Strip State Topic.

Safety Notes

Warning

Power Management Limitations

• Power management affects system safety; operate with caution

• Do not modify power parameters arbitrarily — may cause system damage

• Power-related operations should be performed under expert guidance

Note

Best Practices

• Monitor power status regularly to detect abnormalities early

• Implement monitoring and alert mechanisms for power status

• Implement power protection strategies

• Monitor the temperature and current limits of power modules